fix(prefer-to-have-length): support square bracket accessors (#1010)

* fix(prefer-to-have-length): support square bracket accessors

* refactor(prefer-to-have-length): simplify fixer

* refactor(prefer-to-have-length): simplify fixer further

* chore(prefer-to-have-length): add comments

Author: G-Rath

src/rules/__tests__/prefer-to-have-length.test.ts

@@ -18,16 +18,34 @@ ruleTester.run('prefer-to-have-length', rule, {
     `expect(user.getUserName(5)).resolves.toEqual('Paul')`,
     `expect(user.getUserName(5)).rejects.toEqual('Paul')`,
     'expect(a);',
-    'expect(files["length"]).toBe(1);',
   ],
 
   invalid: [
-    // todo: support this
-    // {
-    //   code: 'expect(files["length"]).toBe(1);',
-    //   errors: [{ messageId: 'useToHaveLength', column: 22, line: 1 }],
-    //   output: 'expect(files).toHaveLength(1);',
-    // },
+    {
+      code: 'expect(files["length"]).toBe(1);',
+      output: 'expect(files).toHaveLength(1);',
+      errors: [{ messageId: 'useToHaveLength', column: 25, line: 1 }],
+    },
+    {
+      code: 'expect(files["length"])["not"].toBe(1);',
+      output: 'expect(files)["not"].toHaveLength(1);',
+      errors: [{ messageId: 'useToHaveLength', column: 32, line: 1 }],
+    },
+    {
+      code: 'expect(files["length"])["toBe"](1);',
+      output: 'expect(files).toHaveLength(1);',
+      errors: [{ messageId: 'useToHaveLength', column: 25, line: 1 }],
+    },
+    {
+      code: 'expect(files["length"]).not["toBe"](1);',
+      output: 'expect(files).not.toHaveLength(1);',
+      errors: [{ messageId: 'useToHaveLength', column: 29, line: 1 }],
+    },
+    {
+      code: 'expect(files["length"])["not"]["toBe"](1);',
+      output: 'expect(files)["not"].toHaveLength(1);',
+      errors: [{ messageId: 'useToHaveLength', column: 32, line: 1 }],
+    },
     {
       code: 'expect(files.length).toBe(1);',
       output: 'expect(files).toHaveLength(1);',
@@ -43,5 +61,10 @@ ruleTester.run('prefer-to-have-length', rule, {
       output: 'expect(files).toHaveLength(1);',
       errors: [{ messageId: 'useToHaveLength', column: 22, line: 1 }],
     },
+    {
+      code: 'expect(files.length).not.toStrictEqual(1);',
+      output: 'expect(files).not.toHaveLength(1);',
+      errors: [{ messageId: 'useToHaveLength', column: 26, line: 1 }],
+    },
   ],
 });

src/rules/prefer-to-have-length.ts

@@ -41,33 +41,24 @@ export default createRule({
           !matcher ||
           !isParsedEqualityMatcherCall(matcher) ||
           argument?.type !== AST_NODE_TYPES.MemberExpression ||
-          !isSupportedAccessor(argument.property, 'length') ||
-          argument.property.type !== AST_NODE_TYPES.Identifier
+          !isSupportedAccessor(argument.property, 'length')
         ) {
           return;
         }
 
         context.report({
           fix(fixer) {
-            const propertyDot = context
-              .getSourceCode()
-              .getFirstTokenBetween(
-                argument.object,
-                argument.property,
-                token => token.value === '.',
-              );
-
-            /* istanbul ignore if */
-            if (propertyDot === null) {
-              throw new Error(
-                `Unexpected null when attempting to fix ${context.getFilename()} - please file a github issue at https://github.com/jest-community/eslint-plugin-jest`,
-              );
-            }
-
             return [
-              fixer.remove(propertyDot),
-              fixer.remove(argument.property),
-              fixer.replaceText(matcher.node.property, 'toHaveLength'),
+              // remove the "length" property accessor
+              fixer.removeRange([
+                argument.property.range[0] - 1,
+                argument.range[1],
+              ]),
+              // replace the current matcher with "toHaveLength"
+              fixer.replaceTextRange(
+                [matcher.node.object.range[1], matcher.node.range[1]],
+                '.toHaveLength',
+              ),
             ];
           },
           messageId: 'useToHaveLength',